Error Accessed None 'CharacterMovement' for seemingly no reason

So pretty much out of nowhere my CharacterBP has gone insane. Here’s the rundown;

My BP is working fine for a while (as in since I made it around 4 days ago) with literally 0 problems.
I create a new AnimInstance and import my character model.
I stick the mesh on the CharacterBP and all is well.
I make a 1D BlendSpace for idle->walking animations as a test
I stick that in the state machine that’s inside my AnimInstance.
Once again, everything is great, my character is animating how it should.
I save after a good days work

Come back a hour or so later to work on it some more and boom, my project is seemingly broken
(I should note I was using 4.9.2 at this time).
Whenever I launch PIE it would crash.
If I launched an executable it would work… Sort of. I couldn’t move my character at all.

I googled it and somebody suggested to delete the Intermediate, the Saved, and the Binary folders. So I did.
The problem still persists.
I then install the new 4.10.1 version and try it out, and to my surprise it doesn’t crash instantly when launching PIE.
Instead it spams me with a million errors.
They all have to do with the BP’s “CharacterMovement”
Here are some screenshots;

Now to my understanding this shouldn’t be a problem. It was working absolutely fine before I starting adding some animations in, But surely that can’t be the cause right? It was working with the animations, but it seems like saving it must have corrupted something in the process.
I even deleted my AnimInstance entirely to see if it would fix the problem, but It was in vain.

Another piece of information that might help is the fact that if I get rid of that entire section of the bp, and use the default movement nodes in the FirstPersonCharacter BP (As in the nodes that are default for the FirstPersonProject Character BP), I can’t move at all.

I truly have no idea how to fix this, any and all help is appreciated.


I made a new character BP and transferred all the nodes and variables over, and it was working 100%, But the original BP is still completely broken. You could mark this answered, but the bug still stands, that original BP somehow got corrupted. But for those with the same problem, you know how to do a temporary fix now

Are you using isValid? checks throughout your BP when referencing Character Movement?

We have not heard back from you in a few days, so we are marking this post as Resolved for tracking purposes. If you are still experiencing the issue you reported, please respond to this message with additional information and we will offer further assistance.